A Density Functional Theory Study on the Hole Transfer in Fullerene Hydride C₆₀H₂

Abstract

The purpose of this study is the analysis of the influence of anisotropic conductivity on magnetic fields and electric potentials by means of phantom measurements. An artificial rotating current dipole was placed in the middle of an anisotropic skein arrangement in a torso phantom filled with saline solution. The signal strength and the change of the shape of potential and field patterns due to anisotropic volume conduction were investigated. Different directions of the dipole were compared to corresponding orientations of measured fields and potentials (angle difference). For electric and magnetic data, the angle difference between observed signal orientations and true dipole orientations continuously increased with the angle between dipole and anisotropy (up to 80 • ) and then decreased back to zero at their orthogonal orientation. Both signal strengths decreased about 10% with an increasing angle between dipole and anisotropy. While the magnetic field showed a generally stronger shape change, the changed shape of the electric potential showed similarity to an extended source. Our phantom study demonstrated that anisotropic compartments influence directions, amplitudes and shapes of potentials and fields at different degrees. We concluded that anisotropic structures should be considered in volume conductor modelling, when source orientation, extension and strength are of interest.

Hydrogenation of Fullerene C60: Material Design of Organic Semiconductors by Computation

“…• Chemical addition can improve hole mobility of C 60 for some isomers [13,14,18]. Conversely, electron mobility of C 60 is not influenced or is decreased by the chemical addition [15].…”

“…Theoretical investigations can give reliable guidelines for the development of such new organic semiconductors. We have also been studying the quantum-chemical design of organic semiconductors based on fullerenes from both scientific and technological viewpoints [11][12][13][14][15][16][17][18][19]. C 60 derivatives (Figure 1) are very interesting from the viewpoint of practical use.…”

“…C 60 derivatives (Figure 1) are very interesting from the viewpoint of practical use. Some types of C 60 derivatives are shown in the figure, and C 60 derivatives of types (a) and (b) have already been studied in our research group [11][12][13][14][15][16][17][18][19].…”

“…However, hole mobility in C 60 film is in the order of 10 −5 cm 2 V −1 s −1 [20], so that C 60 has not been used as a hole-transport material (p-channel semiconductor). Thus, the main purpose of our previous studies [11][12][13][14][17][18][19] was to improve the hole mobility of C 60 that the addition of hydrogen to C 60 would result in a considerable modification of the C 60 materials. This possibility originates from the fact that C 60 has an electronic degeneracy in its cationic state because of its high symmetry I h [21,22], but C 60 hydrides usually do not because of the reduction in symmetry by the addition of hydrogen.…”

“…• Hole and electron mobilities are closely related to the distribution patterns of the HOMO (highest occupied molecular orbital) and the LUMO (lowest unoccupied molecular orbital), respectively [13][14][15]. Delocalized orbitals give high carrier mobility (small reorganization energy) and localized molecular orbitals produce a low carrier mobility (large reorganization energy).…”